Comparison of field-electron emission from different carbon nanotube array structures

Hong

et al. 2014

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Hydrogen absorptions of LaFe 11.5 Si 1.5 compound in 1-atm hydrogen gas at different temperatures are investigated. The hydrogen content in the hydrogenated sample does not increase with the increase of temperature of hydrogen absorption but changes complicatedly. The characteristic of first-order transition in LaFe 11.5 Si 1.5 compound is weakened after hydrogen absorption. It leads the peaks of magnetic entropy to become wider and the hysteresis loss to reduce significantly, but relative cooling power (RCP) is not changed considerably.

Section: Device Design and Fabricationmentioning

confidence: 99%

A novel micro-machined mesh grid for a triode-type carbon nanotube field emitter

Hong

et al. 2014

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“…Then, bilayer catalysts of Al (10 nm) and Fe (1 nm) are deposited by sputtering, and CNT pillars are grown on them by hot-filament chemical vapor deposition (HFCVD) method with the substrate heated to 750 °C by the hot filament (³2000 °C). 33) The CNT pillar length controlled by the growth time is about 400 µm. The final step is to align and bond the three fabricated substrates.…”

Section: Device Design and Fabricationmentioning

confidence: 99%

A triode-type carbon nanotube ionizer for micro mass spectrometer

Hong

et al. 2014

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This article presents an ionizer based on a triode structure for a micromachined time-of-flight mass spectrometer (TOFMS). The fabricated device has two components in one chip: a triode-type field emitter for ionization and an ion separator with acceleration electrodes. The electron emitter is an array of carbon-nanotube (CNT) pillars grown by hot-filament chemical vapor deposition (HFCVD). The anode current measured in the field-emission characteristic test of the fabricated device is high, up to 72.1 µA. The gate current is about 5% of the anode current, which implies low electron interception. We confirmed the ionization by electron impact and obtained the mass spectrum of the air from the fabricated device using a microchannel plate (MCP). The results show that the fabricated TOFMS is feasible for cheap miniature mass spectral analyzers.

“…The shape, dimensions, and layout of the columns are set on the basis of the previous research result. 19,20) The top substrate consists of an anode, a repel electrode, and two acceleration electrodes. The repel and the acceleration electrodes form a space for the ion flight path between the two substrates.…”

Section: Device Structure and Simulationmentioning

confidence: 99%

Field Emission Ion Source Using a Carbon Nanotube Array for Micro Time-of-Flight Mass Spectrometer

Han

Jun

et al. 2011

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In this paper, we present the fabrication and test of a carbon-nanotube (CNT)-based field emission ion source for a micro time-of-flight mass spectrometer (-TOF MS). The -TOF MS is composed of two parts, i.e., a field emission ion source and a mass analyzer. Molecules are ionized by the impact of electrons emitted from CNTs. We calculated the ion beam path using a commercial electrodynamics simulation tool (Simion ver. 7). The results of the ion beam path simulation show that the ions generated in the effective ionization region can pass only between the first acceleration electrode pair. We fabricated a CNT-based field emission ion source for the -TOF MS. The electron current of the field emitter and the ion current of the ion source were measured. Through the characteristic test of a field emission ion source, we confirmed that the fabricated ion source is feasible for the -TOF MS. #